Suppression of cross-reactivity and non-specific binding by antibodies using protein A

Abstract

The structure, formation and use of blocked antibodies, especially those blocked with Protein A, or active fragments of Protein A, are disclosed as well as processes of producing such antibodies. The uses of such blocked antibodies to achieve significant reduction in both specific cross-reaction and non-specific interaction thereby increasing specificity and reactivity with targeted antigenic sites is also described.

Description

FIELD OF THE INVENTION [0001] The present invention relates to the field of antibody-antigen interactions and the use of blocked antibodies to effect significant reduction in both specific cross-reaction and non-specific interaction thereby increasing specificity and reactivity with targeted antigenic sites. BACKGROUND OF THE INVENTION [0002] Antibodies have found great use in the area of diagnostics and for assaying for the presence of antigenic materials in samples such as those derived from biological fluids and for research purposes. A drawback to such successes, however, has been the occurrence of unwanted side reactions in addition to the intended specific reactions of the antibody, which lead to the localization of the antigens under investigation by the specific antibodies used in the assays and the like. [0003] Such unwanted side reactions can include unintended specific reactions, which are frequently considered as cross-reactivity, and which, under certain circumstances, ...

AI Technical Summary

Benefits of technology

[0012] In one aspect, the present invention relates to a blocked immunoglobulin comprising an antibody portion and a Protein A portion. In specific embodiments, such blocked immunoglobulin may comprise in its antibody portion one or more light chain variable regions of an antibody with specificity for a given analyte and / or at least one heavy chain variable region of an antibody. In a preferred embodiment, the present invention provides a blocked immunoglobulin wherein the antibody portion comprises two light chain variable regions and two heavy chain variable regions of an antibody. The protein A portion of said blocked immunoglobulins may contain Protein A or an active fragment thereof.

Problems solved by technology

A drawback to such successes, however, has been the occurrence of unwanted side reactions in addition to the intended specific reactions of the antibody, which lead to the localization of the antigens under investigation by the specific antibodies used in the assays and the like.

In addition, there is the often more troublesome unintended non-specific reactions governed by general physico-chemical properties, such as hydrophobic and electrostatic interactions between the antigen and the antibody.

One drawback of this approach is that preparation of purified Fab fragments is costly and time-consuming.

The use of such mixtures greatly increases the likelihood of non-specific signals, which can significantly reduce the sensitivity and dynamic range of the assay.

Images